Gun



or allA of the joints. Y VVSuch V.welds are indicated by way of example at the several lines indicated byithenumerals V22.V

It may berobserved that in thisv type othV construction it is not necessary toV machine" either the external face ofthegun tubeflO,V

. or the internal `facefof the .jacket 14, exceptV at the contacting areas.v A

A In explanation of the results-attainable by the construction above described, ,let it nbe assumed that oil .oriothergnonffreezing{liquid or solution'iillingtheVV annular chamber l5 Ais maintained therein under extremely .high pressure, V'which mayamount for ex- Vample to 20,000 pounds Vor upward per square ,inch of-surface. There istliereby exerted av corresponding itnernally Ydirected. or Y compressivestress upon the gun tube, the Vpressure being, of course, suitably limited` to I avoid crushing Orl distorting the tube on' the one hand, or disrupting or permanentlydeforming the surrounding jacket ontheother.

It will -be clear that under theseconditions the effective internal pressure, atthe'momentY of firing, tending to detorm orV disrupt the tube, will bev diminished by an amount corresponding to the external Vpressure exertedl at the same moment through theliquid in breaking stress ofthegun.

theA annular chamber.- For example,f `ifthe Yinternal stress developed inthe metal-at the moment of firing is 40,000 pounds Y per square inch, and the inwardly directed stressA duetoVv ,they liquid within the annular chamber is, at l the` same instant, 20,000; pounds, the diti'er-V ential stress, tending to the lateral `deformation of the tube will be .onlyA 20,000 pounds.A 4" By properly `adjustingthe ,internal-f and external pressures, having dueVregardjto the characterv and weightiof metal-in the component parts ofthegun, it thusvbecomes possible to vuse extremely high internal pres.

sures, with correspondingly high muzzle velocitiesand rangewithout danger of exceedingthe elastic limit'lof the metal-or the Furthermore, the hydro taticlpressurefof theliquid is exerted notonly as ajcoinpies-V 'sive stress ,upon the tube, ,but likewise,-by, reasonN Vofthe thrust upon the endwalls of' the annular chamber 15,'as a longitudinal.,

tension'upon .the tube.V "In Yotherwords the.

l tube 'is subjected.simultaneouslyV to a `com;

pressiveV stress and av tensile stress at. right Y angles thereto.V This tensile stress is exerted upon theentire cross-sectional area ofthe tube,',and has the effectief vfurther reducing l its :tendency Vto', lateral fdistertionf or [deforf` fmation under either internallj7V Q01? externally appliedv pressures, .Under these' conditions thefentire cross4 sectional area of the tube be` comes active"injresisting the tendency-.to deformation. 1For given liquid pressure the-amountof this tensile lstress'isof course proportionate tofthe area.'ojftheendV walls of the annular :cha-tuberi, and this chamber is, therefore proportioned in harmony with the general design of the gun to afford the desired-effect;

'To' state the matter otherwise, the longitudinal tension imposedV uponthe fiber of the gun tube tends to utilize the outerbers of the tube, and therefore to equalize thestresses inthe gun ,tubedue to the pressure develope-din the firing chamber. pressure developed in the firing Vchamber causes an excessive stress on the iberot the .tube adjacent the tiring chamber, and this pressurelon the tube isnot transmitted-until acertaindistortion in the tube has taken place., ris therefore necessary. in ordinary gun design to'have a tube of high` elas- Vticlimit,in order that the distortion may extend into the tube and yet notexceed `at any point the elastic limitofthemetal. By application oi a, longitudinal tension to the gun tube Vthere is a constant tendency to `equalize the stress on the fiber adjacent the firing chamber, and Vthus to-utilize 'more Ordinarily the effectively the entire cross-section of the gun tube whenV it` is subjected to the stress of the Vpowder,pressure in the firing chamber.

The hydrostaticpressure of the `liquid in the annularchamber is of course subject to changes of considerable magnitude, owingto.v'olu me changes V 1n the liquid resulting' from temperature variations; aswell as to Y variations in the capacity'ot'V the chamber due -to Va-,like cause. 1 rIhese Variations are toqsomedegree compensating. In addi'- tion to the above, however, the liquid pressureisvsubj ect to rather wide variations due to themomenta'ryreduction in the capacity ofi-the annular chamber by deformation of Y the tube at the moment of firing. rl`his latter variation may be-limited by the prpvisiondl- Y of the lugsl as Vdescribed above; ,1' prefer,

however, to provide VVa gas-cushion properly related tothe liquid volume, onel etl'ect' of such cushion beingto'vabsorb thensudden shocks or.- strains due to theabove varying conditions,V and'more particularly to the re-V duction in the capacity of the annular cham;` ber attheinstant of tiring. Forthis purpose" I have ,provided a heavy-walled gas cham-V ber 23,A communicating, 'with the annular Ychamber l5 Vby means of a` duct 24. If desired the normalfliquid level may Vliel within.

provided, Awhich projects `into 4.the chamber..

andmay be retracted, to compensate for; expansionot the liquid due to rise of temperature, `or .vice Vversa,'thereby 'permitting an a uid'connection between suchchamber and a suitable source of gas orliquid under pressure. F or example in the'modification illustrated VinV Fig. rthe gas-chamber 23a communicates by duct 24 with the 'barrel or firing chamber of" the gun, for example at a point at: which the'gaseousproducts of the Vexplosion 'have expanded to about'A twice their initialv volumeY and hence 4ha'vejfallen 29trepresentsa check-valver or elementV of' like function, for Vpreventing'the gas within thefchamberfrom escaping into the barrel of the gun whileY permitting the gas from the barrel, at mom'en'ts'when excess pressure existsV therein, to VHow into Gthe chamber 23u. YThe effect of this construction is vto produce within the annular chamber or chambers l iai-pressure which may bearV any desired ratio to the pressures existing the firingV chamberV at the moment of'firing, up to the full value of suchpressuresyutilizL ing a portion of the spent gases, at suitable' pressure and temperature, totransmit added Vpressure to the interspace l5.v A'fu'rther advantage is that this pressure is'renewed at each discharge of the gun, thereby com-r pensating for 'lossof pressure by-slowv 'leak-V age or otherv causes..v Obviouslythepresence of. liquid in the annular chamberf isin'ot 'essential, the direct gas Vpressure `beingecpially effective. Ob'riously'a'lso thefluid pressure might be derived from any other suitable source. I

` In case the'fiuid pressure is derived wholly or in parti-from the explosive gases, it may be desirable Vto build upthis pressure gradually, if necessary bythe firing of one or more-preliminary partialcharges. v f

My invention is not limited to 4the use of liquid within the annular chamber or chambers as a means for exerting the Vdesirediinwardly directed pressureupon the gun tube, or tubes, inasmuch V.as I may employ forrthis purpose gases under pressure, Aineli'iding gases liqueiiable under the existingconditions, or even finelyfdivided'andhighly mobilesolids, such asgraphite, which are quite capableY when confined of efectivel-y'transmitting 'applied pressures.

fluid medium employed ini the claims is The expression yintended-to include all cmobile substances capable of accomplishing the purpose herein -set forth.

i' l.' a gun, the combination with a tube and an enveloplngmember' spaced therefrom dinal tensionrby hydrostatic pressurewithin the interspace. Y

V2., In a gun, the `combination with a tube A.and an enveloping member spaced therefrom but united therewith 'at opposite .ends to-provide a closed annular interspace, said -interspace enlarged at one end, whereby the gun-tube may be Vmaintained under longitudinal tension by hydrostatic pressure within the interspace, and means-for varying the eiective'capacity of said interspace and thereby adjusting the hydrostaticv pressure of fluid therein. Y Y AI In a gun', the cembination with a tube and VanY enveloping member spaced therefrom butunited therewith at opposite ends to provide'a closed .interspace, of a` fluid under maintained hydraulic pressure in said interspace, and means for transmitting to saidV fluid added pressure 'from the interior of the gunat the moment of firing. L Ina gun, the combination with a tube and an enveloping `member spaced therefrom but united therewith at opposite ends to provide a closed interspace,l ofV a fluid undermaintainedV hydraulic pressure in said -1nterspace', means for varying the effective capacity of said interspace and thereby adjusting the hydrostatic pressure of fluid therein, and means `for transmitting to said Huid added pressure Afrom the interior `of the gun at the moment of firing.

5. In algun, thecombination with a tube and an enveloping-'member spaced. therefrom but united therewith at oppositeends to provide a closed jinterspace, of a duct between the interior of the Vgun andsaid interspace and a checkvalve for maintaining a fluid under'hydraulic pressure .in the interspace and allo-wing gases from the interior of the gun to pass into'the interspace.`

Y In testimony whereof I affix my signature.

LELAN'D L.; 'Sinn/mRs; 

